Hmm. Dinklage, as always, is great, and I'm really happy to see him with a role that's worthy of him (if you haven't seen "The Station Agent", do).
However, I can't think of any other performances that I'd call more than adequate. And some are less than that. Drogo for one brings nothing to the table - you get none of the charisma that makes him a leader, and more importantly, makes Daenarys love him. He's just there, grunting occasionally.
The show is extremely faithful to the book, which for me isn't always a great thing. Some scenes really feel like they're just reading from the book. They've got all those big elaborate sets, but too often it still comes off small and not very cinematic.
Overall, I'm enjoying it quite a lot and I'll keep watching it. But it's not blowing me away by any stretch.